Various types of linear motors are known in the art and are used for such diverse functions as driving a phonograph turntable and operating a compressor. There is shown in Austrian Pat. No. 195558 and in an article by G. Perronne, entitled "Compresseurs Electromagnetiques Oscillants" appearing in the Bulletin Annexe (Suppl. 2) of the Institut International du Froid, 1958, Vol. 2, pp. 267-278, a compressor which employs a pair of oppositely magnetized permanent magnets disposed within the gap of an AC electromagnet. The magnets are spaced from each other along an axis extending through the gap and move in reciprocal motion along that axis. Although no information as to the efficiency of such compressors is available from the above references, it appears that they are relatively inefficient and require relatively high power electrical inputs.